This invention relates generally to semiconductor devices and, more particularly, to a lead frame which makes possible a cost-efficient semiconductor device assembly process.
Methods of manufacturing semiconductor devices with semiconductor IC chips assembled on a lead frame which is then resin-sealed using a transfer molding method, have been widely adopted to take advantage of mass-production and assembly. Recently, power IC products in which power transistors, along with their control and protection circuits, are assembled on one chip have been developed and distributed widely on the market for use as power supply and control circuits in the power electronics field. Under these circumstances, a demand has been created for a product, which has more than one of these power IC products assembled on a single lead frame, which is then assembled into a resin package with the aim of reducing the size and weight of the semiconductor device.
The basic pattern of conventional lead frames has a chip mount and leads formed corresponding to a semiconductor device. For this reason, if several semiconductor chips are assembled on a lead frame with a basic pattern laid, and accommodated on one package, the number of external leads leading from the package will simply be an integer multiplication value of the number of chips, whereas, in addition to the increase in product size, a problem will arise with the dissipation of heat generated in the semiconductor chips in a construction where a chip mount is formed in the central area of the lead frame onto which semiconductor chips such as power ICs are mounted.
Among the objects of the present invention are: to solve the above problems; to provide an assembly lead frame with high flexibility that corresponds to the semiconductor devices used for diversified applications; and to provide a semiconductor device that realizes size and weight reduction of the product being assembled on the lead frame, with resin-sealed semiconductor devices incorporating various ICs in one package.